As a strip winder for the primary building machine for automotive tires, the apparatus disclosed in Japanese Kokai Patent Application No. 59-207227 is known. This apparatus comprises an anvil for cutting a continuous strip, a transfer conveyer and a brake roller disposed in the order mentioned on one side of the top of a tire building machine, and an overhead vacuum cap adapted to suck up and lift a leading end of the strip which lies on the anvil at the forward end of said conveyer and then to travel forward to bring said leading end of the strip into pressure contact with the tire building drum. In this arrangement, after release of the suction force, the tire building drum is driven nearly one turn to take up said strip thereon, and in this state, the strip on said anvil is cut to length while it is held stationary by said vacuum cap and while the trailing end of the strip which is disposed forwardly of the cutting line is lifted by said vacuum cap, the anvil located rearwardly of said cutting line and the strip on the conveyer are shifted back, together with the conveyer, away from the position under the vacuum cap. Thereafter, said vacuum cap is lowered to join the trailing end of the strip to the leading end of the strip on the tire building drum.
In the above arrangement, however, when the building drum to which the leading end of the strip is secured is driven to wind the strip on the drum, the brake roller at the rear end of the conveyer applies a tension force to the strip to thereby stretch thin and narrow portions of the strip and exaggerate the unevenness of thickness and width. Moreover, while the strip on the anvil is cut, the portion of the strip located behind the cutting line, that is to say on the conveyer side, is kept stationary by clamp means, but since the strip located forwardly of the cutting line, that is to say on the drum side, is loose, the strip is displaced during the cutting operation to cause non-rectilinear cutting so that when the leading and trailing ends of the strip are joined on the drum, either a gap or an overlap is formed at the joint to necessitate subsequent correction, thus making it difficult to implement an automatic production line.